Structural components formed using a system for recycling wet concrete and uses thereof

ABSTRACT

A wet concrete recycling system for mixing trucks returning to the cement plant throughout the workday. “Residual-collection” molds, kept on-hand at the plant, are filled with any excess wet concrete present in the returning trucks. The molds are configured to form finished components such as ground planks, shoring planks, stack wall planks, and the like. The finished components are low in cost due to the use of recycled wet concrete, inexpensive reinforcing materials, and handles/assembly elements fabricated from other recycled materials. The finished components may be sold or leased to customers, thereby converting costs typically associated with traditional residual concrete disposal techniques into supplemental income streams. The finished components may be assembled into a wide variety of useful structures such as temporary covers for road construction/repair excavations, sidewalks, remote/private road surfaces, irrigation ditches, walls, temporary salt domes, mid- to large-size planters, basketball courts, golf driving ranges, community parks, and roadway barriers. All structures assembled from two or more of the finished components are inexpensive due to the low cost of the individual components, easily constructed, and may be permanent or temporary in nature.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to U.S. Provisional Application Ser. No.60/535,450, filed 8 Jan. 2004, entitled “System for recycling wetconcrete into precast structures and structures formed thereby.”

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to efficiently recycling concrete wastefrom ready-mix cement trucks. More particularly, the present inventionrelates to a system for recycling excess wet concrete, the structuralcomponents formed thereby, and the myriad of beneficial uses that existfor those components.

2. Discussion of the Background

Often times ready-mix concrete trucks return to the cement yard at theend of the work day with relatively large amounts of excess freshconcrete. This excess fresh concrete must be disposed of or recycled insome manner, so that the cement trucks may be cleaned for the next day'soperations.

The typical disposal process has long involved wetting down the concretewithin the mixing truck itself to significantly dilute it, and thendumping the wet concrete. This wet concrete is then held in a bin forapproximately five days, during which time the particulate separatesfrom the water. After separation of the excess water, the solid materialis moved to a drying bin and after some period it is transported to alandfill. This disposal process results in a significant waste of refusesolid material, and a large added cost of transportation and disposal ofthe refuse solid material. Moreover, cities are now beginning to wrestlewith the problem of storing refuse solid material inasmuch as vast pilesof it are collecting at many landfills. As a result, a number ofprocesses have been attempted to recycle the residual concrete, albeitall have generally been directed towards recovery of the concreteaggregate (i.e. landfill material).

One method, well-known in the industry, for recycling excess freshconcrete includes having the mixing truck operators dump the excessconcrete into on-site molds. Once the concrete hardens it is removedfrom the mold and fed into a breaking, or crushing device. The concreteis broken or ground into small pieces which are sold to constructionsites for use as base fill for foundation, sub-foundation, or roadbedprojects.

Other examples of recycling excess concrete are found in U.S. Pat. Nos.5,908,265 to Mostkoff (disclosing a method and apparatus for producingconcrete shapes suitable for use in forming an artificial reef usingready mix cement trucks with excess load to blend measured amounts ofconcrete and tire chips), U.S. Pat. No. 5,766,524 to Rashwan et al.(disclosing a method and apparatus for the reclamation of excessconcrete returned to the cement yard by cement delivery trucks usingmolds designed to produce blocks of concrete suitable for regrindinginto aggregate), and U.S. Pat. No. 3,786,997 to Viner (disclosing a wetconcrete reclamation method and apparatus in which unused concrete ispoured and formed, and then crushed into little pieces).

Additionally, the use of molds to form concrete into various componentshapes is also well-known in the industry. For example, U.S. Pat. No.5,096,648 to Johnson et al. discloses a mold system for producing pavingstones that employs a plurality of slidably mounted molds, and U.S. Pat.No. 4,067,941 to Gaudelli et al. discloses a mold for producing multipleslabs of concrete. However, the conventional techniques for moldingconcrete into pre-cast components such as paving stones or simple slabsare not suitable for the contemplated uses of the components molded fromthe recycled material of the present invention for the followingreasons. Historically, the process of removing the hardened concretecomponents from molds is a time consuming and expensive because greatcare must be taken to ensure that the molded component is not damaged.Moreover, the resulting pre-cast components are not strong enough to beused as ground, shoring or stack wall planks because they are notreinforced. Finally, the resulting components are not easily manipulatedand stacked because they are not made with integral or attachablelifting handles.

Therefore, there remains a need in the art for an efficient and costeffective system for recycling excess wet concrete from ready-mixconcrete trucks into components that possess a variety of beneficialuses. To the best of the knowledge of the present inventor, no prior artsystem addresses this need. A system of this type should provide for thepouring of residual wet concrete into molds to make pre-cast componentssuch as ground planks, shoring planks, stack wall planks, and the like.Once the concrete has set, the resulting components should be easy toremove from the mold and stackable so that they may be stored ordisplayed for sale. Steel reinforcing materials, lifting handles, and/orelements that assist in the assembly of two or more components should beincluded to make the concrete components stronger and easier tomanipulate and configure.

Furthermore, the pre-cast concrete components should be configured suchthat they may be used in the construction of a wide variety ofbeneficial structures. The structures assembled from two or more of theconcrete components should be inexpensive, easily constructed, andpermanent or temporary in nature.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide componentsformed by an efficient and cost-effective system that recycles wetconcrete waste material from ready-mix cement trucks into“residual-collection” molds.

It is another object of the present invention to provide componentsformed from recycled wet concrete that are easily removed from themolds.

Yet another object of the present invention is to provide componentsformed from recycled wet concrete that are ready-to-use and structurallysound.

It is another object of the present invention to provide componentsformed from recycled wet concrete such as ground planks, shoring planks,stack wall planks, and the like.

An additional object of the present invention is to provide componentsformed from recycled wet concrete that include integral or attachablelifting handles or rings for easy handling on a work site.

Still another object of the present invention is to provide componentsformed from recycled wet concrete that include reinforcing materials toincrease structural strength.

Another object of the present invention is to provide components formedfrom recycled wet concrete that include elements that assist inassembling two or more components.

It is another object of the present invention to provide componentsformed from recycled wet concrete that are stackable so that they may bereadily stored or displayed for sale.

Yet another object of the present invention is to provide componentsformed from recycled wet concrete that are inexpensive to manufactureand sell.

It is still another object of the present invention to providestructures comprising one or more of the recycled concrete componentsthat have a myriad of beneficial uses.

An additional object of the present invention is to provide structurescomprising one or more of the recycled concrete components that areinexpensive and easily constructed.

Still another object of the present invention is to provide structurescomprising one or more of the recycled concrete components that arepermanent or temporary in nature.

The present invention addresses these and other objects by providing asystem that begins with concrete mixing trucks returning to the cementplant throughout the workday. “Residual-collection” molds, kept on-handat the plant, are filled with any excess wet concrete present in thereturning trucks. The molds are configured to form pre-cast componentssuch as ground planks, shoring planks, stack wall planks, and the like.

Once the concrete has set, the resulting components are strong, yet easyto remove from the molds and manipulate (e.g. stack), due to thepresence of integral reinforcing materials and integral or attachablelifting handles. In that way, they may be stored or displayed for sale.Also integral to the finished components are elements that assist in theassembly of two or more components. The finished components are low incost due to the use of recycled wet concrete, inexpensive reinforcingmaterials (e.g. “rebar”), and handles/assembly elements fabricated fromother recycled materials (e.g. PVC). The finished components may be soldor leased to customers. This converts the incremental costs typicallyassociated with traditional residual concrete disposal techniques intosupplemental income streams based upon the present invention's novel useof recycled wet concrete.

The lifting handle/ring may be either a length of bent rebar that is anelement of the integral reinforcing materials, or a pre-engineered,integral or attachable, PVC or plastic handle, capable of supporting300% of the pre-cast component's weight. When an integral handle ispresent, bolt cutters may be used to remove the handle as necessary oncethe component is in place at a work site. In another embodiment, thehandle may be attached to the component via a hinge such that it liesflat against a surface of the component when not in use. In yet anotherembodiment, a cylindrical section of PVC may be used to form a pre-casthole in the structure. Once the concrete has set, the PVC sleeve may beremoved and a swage bolt may be inserted for use as a handle.

The system of the present invention also provides components withintegral patterns, textures, and/or colors. Specifically, wet concreteis poured into the mold, and then screeded and floated to create asurface that is smooth and suitable for finishing with a pattern,texture, and/or color. The concrete may then be embossed with a desiredpattern or texture via the use of a heavy roller that is rolled over thetop of the mold. The roller is grooved on its outer edges, and atpre-determined intervals, to provide for proper guidance over the moldand/or to ensure that the pattern is appropriately aligned and embossedto a constant depth. Colors and/or other textures may be added byconventional methods such as the application of a thin layer of exposedaggregate or brick dust.

Once complete, the pre-cast concrete components may be assembled into awide variety of useful structures. For example, the ground planks of thepresent invention may be used in place of, or as a supplement to,sub-grade/fill materials particularly in heavy/high traffic areas, astemporary covers for excavations necessitated by roadconstruction/repair, and in the construction of sidewalks,remote/private road surfaces, or irrigation ditches. Shoring planks, forexample, may be used in conjunction with soldier piles in trenches forutilities/infrastructure repair or installation, and excavationsassociated with construction projects. Stack wall planks, for example,may be used in the construction of all types of walls, temporary saltdomes, and mid- to large-size planters. Moreover, a variety of urbanrenewal and temporary land reclamation projects involving structuressuch as basketball courts, golf driving ranges, or community parks maybe constructed using a combination ground and stack wall planks.

A common element is that all structures assembled from two or more ofthe concrete components are inexpensive due to the low cost of theindividual components, easily constructed, and may be permanent ortemporary in nature.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of a casting bed 15 including aplurality of molds 18 (or “forms”) used to create ground planksaccording to a preferred embodiment of the present invention.

FIG. 2 is a cross-sectional side view of a ground plank 20 illustratingthe reinforcing material 21 and an integral bent rebar-type liftinghandle 30.

FIG. 3 is a cross-sectional side view of a ground plank 20 illustratingan alternative integral pre-engineered PVC-type lifting handle 32. Thereinforcing material 21 of FIG. 2 is not shown.

FIG. 4 is a cross-sectional side view of a ground plank 20 illustratingan alternative attachable swage bolt-type lifting handle 34. Thereinforcing material 21 of FIG. 2 is not shown.

FIG. 5 is a cross-sectional front view of a ground plank 20 illustratinga hinged lifting handle 36. The reinforcing material 21 of FIG. 2 is notshown.

FIG. 6 is a cross-sectional side view, taken along A-A, of the groundplank 20 of FIG. 5. The reinforcing material 21 of FIG. 2 is not shown.

FIG. 7 is a top perspective view of a ground plank 20 illustrating theuse of a roller 41 to emboss a pattern or texture 40 on the surface ofthe plank 20.

FIG. 8 is a cross-sectional side view of a loading dock/zone 100 showingthe use of the ground plank 20 of FIG. 2 or 3.

FIG. 9 is a cross-sectional view of an irrigation ditch 140 showing theuse of the ground plank 20 of FIG. 2 or 3.

FIG. 10 is a cross-sectional view of a road surface 180 showing the useof the ground plank 20 of FIG. 2 or 3 as installed in a shallowexcavation 182.

FIG. 11 is a top perspective view of a shoring plank 60 according to analternative embodiment of the present invention and its use inconjunction with two soldier piles 70.

FIG. 12 is a front perspective view of the shoring planks 60 and soldierpiles 70 of FIG. 11.

FIG. 13 is a front perspective view of a plurality of stack wall planks80 according to an alternative embodiment of the present invention andtheir use in the construction of a stack wall 220.

DETAILED DESCRIPTION

The present invention is a series of pre-cast structural componentsfabricated of the recycled excess or residual wet concrete remaining inready-mix concrete trucks after completion of a job, and a variety ofbeneficial uses for those components.

The recycling of the excess or residual wet concrete begins with themixing trucks returning to the plant during and at the end of theworkday. “Residual-collection” molds are kept on-hand at the plant, andas the ready-mix cement return they evacuate their excess wet concreteinto the residual-collection molds. The molds are configured to formpre-cast structural components such as ground planks, shoring planks,stack wall planks, and the like.

FIG. 1 is a plan view of a casting bed 15 sectioned to include aplurality of molds 18 for creating ground planks from recycled concrete,according to a preferred embodiment of the present invention.

As stated above, at the end of a workday it is common for returningtrucks to be carrying more than a quarter cubic yard of excess wetconcrete. To recycle this wet concrete, portable or stationary“residual-collection” molds 18 are kept on-hand at the plant, and as theready-mix cement trucks return they evacuate their excess wet concreteinto the residual-collection molds 18. Over the course of days or weeksthe molds 18 are filled to create a plurality of completed, precastconcrete planks as will be described. Upon completion, the planks areremoved and inventoried, and the process begins anew. In the meantime,the completed planks are sold or leased to customers. This not onlyavoids the incremental cost associated with the traditional disposal ofconcrete aggregate, but also produces a supplemental income stream fromit.

The “residual-collection” molds 18 of the present invention include acasting bed 15 for molding concrete into planks. FIG. 1 is a topperspective view of a casting bed 15 including a plurality of molds 18(or “forms”) used to create ground planks according to a preferredembodiment of the present invention. The casting bed 15 is comprised ofrectangular steel plate flooring 14, four steel plate perimeter walls16, a plurality of lengthwise steel plate dividers 17, and one or morewidthwise steel plate dividers 13.

The perimeter walls 16 and the dividers 17, 13 are preferably formed inthe shape of narrow-angle triangles, apex pointed upward, in which thesymmetrical sides are comprised of strips of steel plate, stitch weldedtogether along the apex. These angular perimeter walls 16 and dividers17, 13 are necessary to ensure that the cast form is easily removed fromthe mold 18 once set. The bottom of the perimeter walls 17, 13 may betack welded along the steel plate flooring 14 to form an enclosed andsectioned rectangular form.

In one particular embodiment of the casting, a full-length mold 18 isconfigured to produce 12″ wide×12′ long×6″ thick ground planks. A groundplank 20 of this size requires approximately a quarter cubic yard ofconcrete and is, relatively speaking, small and light enough to beeasily manipulated (i.e. stacked, displayed for sale). Widthwise steelplate dividers 13 are employed to create alternative smaller molds 19 tocreate planks 20 that are, for example, half the length (i.e. 6 feet) ofthose created by the full-length mold 18. Those skilled in the art willappreciate that planks 20 of other lengths may be fabricated in thismanner without diverting from the spirit of the present invention.

FIGS. 2-6 are cross sectional views of ground planks 20 formed inaccordance with the above-described recycling method using the castingbed 15 of FIG. 1 The ground planks 20 preferably are equipped with oneor more lifting handles 30, 32, 34, 36, and integral reinforcement, suchas commercially available welded wire mesh or steel rebar, as will bedescribed.

FIG. 2 shows a plank 20 incorporating a pre-formed reinforcing cage 21.The reinforcing cage 21 may be constructed from two layers ofconventional welded wire mesh 26 with each layer supported by a pair ofcommercially available 2″ continuous slab bolsters 27. Those skilled inthe art will appreciate that other forms of concrete reinforcement (e.g.steel rebar) may also be suitable for the purpose of reinforcing theplanks 20 of the present invention. The reinforcing cage 21 isintroduced into the casting bed 15 prior to recycling of the concrete,such that poured concrete will submerge the reinforcing cage 21 andharden around it.

Additionally, in order for the planks 20 to be easily removed from themolds 18 (FIG. 1) and manipulated, the planks 20 are preferably formedwith one or more fixedly (i.e. integral) or removably attached liftinghandles. For safety reasons, the lifting handles should be rated to holdup to 300% of the plank's weight. As seen in FIG. 2, a bent rebarlifting handle 30 is wired or otherwise attached to the pre-formedreinforcing cage 21 and thereby becomes an integral part of the plank20.

FIG. 3 is a cross-sectional side view of a ground plank 20 illustratingan alternative integral pre-engineered PVC-type lifting handle 32. Inboth cases the lifting handles 30, 32 should extend approximately fourinches above the surface of the plank 20 to allow a standard hookconnected to a piece of lifting equipment (e.g. a front-end loader witha boom) may be used to lift and move the plank. If necessary forstructural or aesthetic reasons, the lifting handles 30, 32 may beeasily removed by bolt cutters once the plank 20 is in properlypositioned. The lifting handles 30, 32 are introduced into the castingbed 15 during the recycling process after the concrete has attained adesired height within the mold 18, such that subsequently-pouredconcrete will harden around the ends of the lifting handles 30, 32 andanchor them in the plank 20.

In another embodiment of the ground plank 20 of the present invention,as shown in FIG. 4, the lifting handle 34 is removably attached to theplank 20. A hole 35 for use with an attachable handle 34 is created byplacing a plugged PVC sleeve 33 into wet concrete present in a mold 18(FIG. 1) at the desired handle location. Once the concrete has set, thesleeve 33 may be removed and a commercially available swage bolt 34 maybe inserted/attached for use as a handle. This is the preferred type ofhandle for planks 20 with surface finishes such as textures, patterns,and/or colors (see discussion below) because, once the plank 20 isproperly positioned, the handle 34 may be removed and the pre-cast hole35 may be filled in and camouflaged.

In yet another embodiment of the ground plank 20 of the presentinvention, that shown in FIGS. 5 and 6, a lifting handle 36 comprising ahinge 37 may be either integrally attached as with the rebar handle 30of FIG. 2 or the pre-engineered PVC 32 handle of FIG. 3, or removablyattached as with the swage bolt handle 34 of FIG. 4. The hinge 37 ispositioned at the surface of the plank 20. Additionally, a piece ofmaterial approximating the size and shape of the lifting handle 36 isplaced proximate the hinge 37, on the surface of the wet concrete heldwithin the mold 18 (FIG. 1), to create a void 38 in the surface of theplank 20. This void 38 permits the lifting handle 36 to pivot at itshinge 37 and lie flush with the smooth surface of the plank 20. Thistype of handle 36 is ideally suited for ground planks 20 used astemporary road surfaces, where easy and efficient transfer of the planks20 from one location to another is typically required.

The recycling method and planks 20 formed thereby according to thepresent invention can be post-cured with integral colors, texturesand/or patterns. After the surface of the recycled concrete is madesmooth and suitable for taking a finish by traditional means (i.e.screeding, floating), colors and/or textures may be added byconventional methods such as applying exposed aggregate or brick dust,or by simply running a broom over the wet concrete. As shown in FIG. 7,selected patterns or textures 40 (i.e. layered brick-like pattern) maybe also be embossed in the surface of a plank 20 by a heavy roller 41formed with the pattern 40 on its exterior surface. The roller 41 of apredetermined length is rolled over the top surface of the recycledconcrete held in a mold 18 (FIG. 1) to emboss the pattern. The roller 41includes grooves 42 on its outer edges, and, when necessary, atpredetermined intervals, to guide it along the walls of the mold 18 toensure that the pattern is aligned and embossed to a constant depth.

The casting bed 15 of FIG. 1, as indicated above, may be configured toproduce planks with different dimensions. For example, planks may beformed that are 24″ wide×12′ long×6″ thick (approximately a half cubicyard of wet concrete) or 36″ wide×24′ long×8″ thick (approximately 1.75cubic yards of wet concrete). The ground planks 20 of FIGS. 1-7 havemany beneficial uses limited only by their non-specified compressivestrength and a user's imagination.

For example, ground planks 20 may be used in place of, or as asupplement to, sub-grade or fill materials in heavy/high traffic areas.Areas subject to heavy traffic, in terms of weight and frequency of use,include construction site entrances/exits and loading docks/zones 100 asshown in FIG. 8's cross-sectional view. Use of the planks 20 in aloading dock/zone 100 may be as a supplement to some form of gravel 102,wherein the planks 20 are positioned beneath the gravel 102 to preventits dispersal or ingress into the underlying ground 104, creating theneed to replace it. Any standard asphalt paving material 106 may beapplied to create the finished road surface 108. Alternatively (notshown in the Figures, the planks 20 may be used to replace traditionalsub-grade/fill materials and provide a more stable platform on which thetypical asphalt paving material may be applied directly. Theseconfigurations reduce the frequency of re-paving operations.

High traffic zones (i.e. high frequency of use/travel, but relativelylightweight vehicles) where the ground planks 20 of the presentinvention may be applied beneficially include the shed/barn entrancesfound on farms, which often seem to be perpetually wet and subject tosignificant rutting. When deployed in these zones, the planks 20 may beset directly upon undisturbed ground, or situated in a shallowexcavation that places the top surface of each plank 20 roughly flushwith the surface of the surrounding ground.

The ground planks 20 may also be used, in place of the traditional steelplates, as temporary covers for excavations necessitated by roadconstruction/repair or the trenches that accompany the installation ofunderground utilities or infrastructure. When used in this manner, it ispreferable that the planks be recessed into the road surface such thatthe top surface of each plank is flush with the surrounding roadsurface. The ground plank 20 embodiment of FIGS. 5 and 6 areparticularly beneficial to this type of application due to the existenceof hinged handles that sit flush to the surface of the plank 20 when notbeing used.

The planks 20 may be installed as temporary bridges over narrow ditches(e.g. irrigation ditches) and waterways while permanent solutions areconstructed. As shown in FIG. 9's cross-sectional view, the groundplanks 20 may even be used to line an irrigation ditch 140 such that theerosion of the underlying soil 142 by the flow of water 144 is minimizedand/or eliminated.

Yet another use of the ground planks 20 of the present invention, asshown in FIG. 10's cross-sectional view, may be in the construction ofroad surfaces 180 that are temporary, or permanent rural (i.e. remote)or private road surfaces, such as driveways or farm roads, that are notsubject to significant use. Their use in this type of application may beas a replacement for, or as a supplement to, some form of gravel. Asdiscussed above with respect to FIG. 8, when used as a supplement togravel, the planks 20 are positioned beneath the gravel to prevent itsdispersal or ingress into the underlying ground. When used withoutaccompanying gravel, as shown in FIG. 10, the planks 20 may be situatedin a shallow excavation 182 that places the top surface of each plank 20roughly flush with the surface of the surrounding ground 184.Alternatively, the planks 20 may be set directly upon undisturbedground. The road surface 180 may be constructed by positioning theplanks perpendicular (as in FIG. 10) or parallel to the direction oftravel on the road.

Finally, the ground planks 20 may be used in the construction ofsidewalks/walkways. Once again, planks 20 used in this manner may beplaced directly upon undisturbed ground, or situated in a shallowexcavation that places the top surface of each plank 20 roughly flushwith the surface of the surrounding ground. The ground plank 20embodiments of FIGS. 4 and 7 are particularly beneficial to this type ofapplication due to the ability to hide/camouflage the means forhandling/moving the plank 20 and the existence of a surface pattern,texture, and/or color that enhances their aesthetic qualities.

In each of the above-described applications, the compressive strength ofthe set, recycled concrete forming the finished ground planks 20 isindeterminate, and inconsequential. The ground planks 20 of the presentinvention are not intended for applications requiring well-definedcompressive strength parameters such as those with extremely highstress/load requirements (e.g. interstate highways, buildingfoundations, bridge piers). Such planks 20 are ideal for drivewaysurfaces, sidewalks, garden retaining walls, and the like because theyare aesthetically pleasing and require less labor to install thantraditional pavers or stones.

Alternative embodiments of the pre-cast planks of the present inventioninclude shoring planks 60 with notches formed at their ends (forinteraction with soldier piles 70 as discussed below with respect toFIGS. 11 and 12) and stack wall planks 80 with through holes proximatetheir ends (for alignment and assembly purposes as discussed below withrespect to FIG. 13).

The shoring planks 60 of the present invention may be used in theconstruction of the trenches typically required by the installation orrepair of underground utilities/infrastructure, or during the excavationof a building's foundation. A plurality of planks 60 are typically usedin conjunction with a plurality of soldier piles 70 to construct ashoring wall 75 such as that shown in FIGS. 11 and 12. Commerciallyavailable soldier piles 70, comprising a substantially I-shapedcross-section, are driven vertically into the ground 78 at distanceintervals approximately equal to the length of a plank 60. Notches 62are preferably formed at each end of the planks 60 and are designed tointeract with the soldier piles 70 such that each plank 60 may besupported in a vertical orientation between two piles 70.

Multiple planks 60 may be stacked vertically depending upon the depth ofthe trench or excavation. Gaps 72, to allow for water drainage, areformed in the shoring wall 75 by positioning spacers 74 in the recessesof the soldier piles 70 between each pair of planks 60. The spacers 74are preferably short sections of a commercially available plastic rodmaterial (e.g. recycled PVC) possessing sufficient compressive strengthto support the weight of several planks 60 stacked vertically. Soilingress into the trench/excavation is prevented by spanning the gaps 72with a commercially available, porous material (e.g. filter cloth) thatallows water, but not dirt/soil, to pass through.

By providing for water drainage from behind the shoring wall 75 throughthe gaps 72, the horizontally oriented forces exerted on the wall 75 bythe ground 78 are reduced to the point where the indeterminatecompressive strength of the set, recycled concrete forming the finishedplanks 60 is inconsequential. The shoring planks 60 of the presentinvention are, just like the ground planks 20 described above, notintended for applications requiring well-defined compressive strengthparameters.

The stack wall planks 80 of the present invention may be used toconstruct stack walls 220, such as that shown in FIG. 13, of varying(i.e. user-defined) lengths and heights. This may be accomplished byforming each plank 80 with a hole 82, running through the plank'sthickness, proximate each end. In constructing a stack wall 220, eachlayer of planks 80 is offset from the layer immediately below with theholes 82 aligned vertically. Vertical alignment of the holes 82 allows arod 84 to be inserted through the multiple layers of planks 80 toincrease the structural integrity of the wall 220 with respect tohorizontally applied forces. Each rod 84 is preferably a length ofcommercially available metal such as round rebar.

Stack walls 220 may, for example, be used to construct the temporarysalt domes (with roofs formed by sheet of water-resistant, recycledplastic) required only in years where an excessive amount of winterweather is expected (i.e. necessitating the stockpiling of an amount ofsalt/chemicals greater than the storage capacity of all permanent saltdomes), or mid- to large-size planters using sections of filter cloth toretain the enclosed soil. The gaps 90 formed by the offsetting of theplanks 80 of each layer serve to minimize any horizontally orientedforces that may be exerted on the wall 220 such that the indeterminatecompressive strength of the set, recycled concrete forming the finishedplanks 80 is inconsequential. Just as with the ground planks 20 andshoring planks 60 described above, the stack wall planks 80 of thepresent invention are not intended for applications requiringwell-defined compressive strength parameters.

Those skilled in the art will appreciate that ground planks 20, shoringplanks 60, and stack wall planks 80 may be combined to create any one ofa virtually unlimited number of different structures without divertingfrom the spirit of the present invention. For example, an alternativeform for a ground plank fabricated from recycled concrete is that of theparking curbs used in parking lots/garages to separate one parking spotfrom the next. The planks 20, 60, 80 may be combined to form largerstructures, including, but not limited to, basketball courts, golfdriving ranges, manholes and manhole covers, and community parks, may bepermanent or temporary in nature and may be used in a variety of urbanrenewal and/or temporary land reclamation projects.

A basketball court may be constructed, once the backboard supports havebeen anchored, using ground planks 20 to form the court surface, stackwall planks 80 in the assembly of a stack wall surrounding the court,and a combination of ground and stack wall planks 20, 80 to create avariety of seating surfaces (e.g. benches, stands/bleachers) for theplayers and spectators. A golf driving range may be constructed usingground planks 20, underlying a series of appropriately spaced artificialgrass mats, to form the hitting surfaces, stack wall planks 80 orshoring planks 60 combined with soldier piles, in the assembly ofbarriers between each hitting surface (i.e. artificial grass mat), and acombination of ground and stack wall planks 20, 80 to create a varietyof seating surfaces for the participants and/or observers.

Square manholes may be constructed using shoring planks 60 (with gaps inbetween as above in FIG. 12) combined with soldier piles to form thevertical walls, with the manhole covers being formed from ground planks20, possibly formed as a square (e.g. 48″×48″×6″ thick), instead of arectangle, and equipped with a hinged handle that, when not in use, fitswithin a recess formed in the surface of the plank (see FIGS. 5 and 6).The cover may be connected to the manhole via a hinge that is preferablyfabricated of recycled PVC. Finally, a community park, or an area ofcommon ground, may be constructed using ground planks 20 to formwalkways and courtyards/plazas, stack wall planks 80 or shoring planks60 combined with soldier piles, in the assembly of barriers around orwithin the park, and a combination of ground and stack wall planks 20,80 to create a variety of seating surfaces for visitors.

All of the structures assembled from two or more of the recycledconcrete planks 20, 60, 80 are inexpensive due to the minimal cost ofthe individual components, easily constructed due to the various meansof assembly, and permanent or temporary in nature depending upon theneeds of the application.

Having now fully set forth the preferred embodiments and certainmodifications of the concept underlying the present invention, variousother embodiments as well as certain variations and modifications of theembodiments herein shown and described will obviously occur to thoseskilled in the art upon becoming familiar with said underlying concept.It is to be understood, therefore, that the invention may be practicedotherwise than as specifically set forth in the appended claims.

1. A precast concrete plank formed by recycling wet surplus concrete incement trucks returning from a worksite, said recycling comprisingprogressively emptying said surplus concrete into a residual-collectionmold over the course of time until the recycled concrete builds into oneor more completed precast concrete planks, said residual-collection moldfurther comprising a casting bed including a rectangular steel platefloor, four steel plate perimeter walls, and a plurality of lengthwiseand widthwise steel plate dividers each having a tapered cross-section,said precast concrete plank further comprising: a concrete plank moldedand hardened in said casting bed and having at least one embeddedlifting handle protruding upwardly therefrom, and an integralreinforcement structure embedded throughout said concrete plank.
 2. Theprecast concrete plank according to claim 1, wherein said lifting handleis fixedly attached to said plank.
 3. The precast concrete plankaccording to claim 1, wherein said lifting handle is removably attachedto said plank.
 4. The precast concrete plank according to claim 1,wherein said plank further comprises at least one texture embossed in asurface of said plank.
 5. The precast concrete plank according to claim1, wherein said plank further comprises at least one pattern embossed ina surface of said plank.
 6. The precast concrete plank according toclaim 1, wherein said plank further comprises at least one color appliedto a surface of said plank.
 7. The precast concrete plank according toclaim 1, wherein said plank further comprises notches formed at each endof said plank.
 8. The precast concrete plank according to claim 1,wherein said plank further comprises holes formed proximate each end ofsaid plank.
 9. The precast concrete plank according to claim 1, whereinat least one of said planks is used as a replacement for sub-grade/fillmaterials.
 10. The precast concrete plank according to claim 1, whereinat least one of said planks is used as a supplement to sub-grade/fillmaterials.
 11. The precast concrete plank according to claim 1, whereinat least one of said planks is used for traversing excavations, ditches,waterways, and the like.
 12. The precast concrete plank according toclaim 1, wherein at least one of said planks is used to prevent soilerosion.
 13. The precast concrete plank according to claim 1, wherein atleast one of said planks is used to construct surfaces supporting thepassage of people, vehicles, animals, and the like.
 14. The precastconcrete plank according to claim 7, wherein at least one of said planksis used in conjunction with at least two soldier piles to constructshoring walls in trenches, excavations, and the like.
 15. The precastconcrete plank according to claim 8, wherein at least two of said planksare used in conjunction with at least one alignment rod to constructstack walls.
 16. Structures comprising: one or more first precastconcrete planks formed by recycling wet surplus concrete in cementtrucks returning from a worksite, said recycling comprisingprogressively emptying said surplus concrete into a residual-collectionmold over the course of time until the recycled concrete builds into oneor more completed first precast concrete planks, saidresidual-collection mold further comprising a casting bed including arectangular steel plate floor, four steel plate perimeter walls, and aplurality of lengthwise and widthwise steel plate dividers each having atapered cross-section, each of said one or more first precast concreteplanks being molded and hardened in said casting bed and furthercomprising at least one embedded lifting handle protruding upwardlytherefrom, and an integral reinforcement structure embedded throughoutsaid first plank; and one or more second precast concrete planks formedby recycling wet surplus concrete in cement trucks returning from aworksite, said recycling comprising progressively emptying said surplusconcrete into a residual-collection mold over the course of time untilthe recycled concrete builds into one or more completed second precastconcrete planks, said residual-collection mold further comprising acasting bed including a rectangular steel plate floor, four steel plateperimeter walls, and a plurality of lengthwise and widthwise steel platedividers each having a tapered cross-section, each of said one or moresecond precast concrete planks being molded and hardened in said castingbed and further comprising at least one embedded lifting handleprotruding upwardly therefrom, an integral reinforcement structureembedded throughout said second plank, and notches formed at each end ofsaid second plank.
 17. Structures according to claim 16, furthercomprising one or more third precast concrete planks formed by recyclingwet surplus concrete in cement trucks returning from a worksite, saidrecycling comprising progressively emptying said surplus concrete into aresidual-collection mold over the course of time until the recycledconcrete builds into one or more completed third precast concreteplanks, said residual-collection mold further comprising a casting bedincluding a rectangular steel plate floor, four steel plate perimeterwalls, and a plurality of lengthwise and widthwise steel plate dividerseach having a tapered cross-section, each of said one or more thirdprecast concrete planks being molded and hardened in said casting bedand further comprising at least one embedded lifting handle protrudingupwardly therefrom, an integral reinforcement structure embeddedthroughout said third plank, and holes formed proximate each end of saidthird plank.
 18. Structures comprising: one or more first precastconcrete planks formed by recycling wet surplus concrete in cementtrucks returning from a worksite, said recycling comprisingprogressively emptying said surplus concrete into a residual-collectionmold over the course of time until the recycled concrete builds into oneor more completed first precast concrete planks, saidresidual-collection mold further comprising a casting bed including arectangular steel plate floor, four steel plate perimeter walls, and aplurality of lengthwise and widthwise steel plate dividers each having atapered cross-section, each of said one or more first precast concreteplanks being molded and hardened in said casting bed and furthercomprising at least one embedded lifting handle protruding upwardlytherefrom, and an integral reinforcement structure embedded throughoutsaid first plank; and one or more second precast concrete planks formedby recycling wet surplus concrete in cement trucks returning from aworksite, said recycling comprising progressively emptying said surplusconcrete into a residual-collection mold over the course of time untilthe recycled concrete builds into one or more completed second precastconcrete planks, said residual-collection mold further comprising acasting bed including a rectangular steel plate floor, four steel plateperimeter walls, and a plurality of lengthwise and widthwise steel platedividers each having a tapered cross-section, each of said one or moresecond precast concrete planks being molded and hardened in said castingbed and further comprising at least one embedded lifting handleprotruding upwardly therefrom, an integral reinforcement structureembedded throughout said second plank, and holes formed proximate eachend of said second plank.